Fetching Data through Hibernate without passing Primary Key

Question

I am using a composite primary key which is defined in Entity Class as :

@EmbeddedId
private ParticipantPrimaryKey pKey;

and the primary Key consists of Event Id and Student Id which are defined in PrimaryKey Entity Class.

Now i need to fetch the participants from the table which are participating in any particular Event.

The HQL query that is not working due to above problem:

select pe from ParticipantEntity pe where pe.eventId=?

If i use any other field then it'll work as they are present in the Entity Class but the Event ID is there in the primaryKey Entity.

Answer 1

You can use @ClassId , like :

 @ClassId(ParticipantPrimaryKey.class)
 class ParticipantEntity { ...

Remove from the ParticipantEntity :

@EmbeddedId
private ParticipantPrimaryKey pKey;

And also in the ParticipantEntity , add the two keys:

@Id
private Long eventId;

@Id
private Long studentId;

After that, you can just:

SELECT pe FROM ParticipantEntity pe where pe.eventId = :eventId